TABLE 3.

Meta‐analysis; mortality rate of influenza type and subtypes in different age ranges

	Age groups (year)	Mortality rate (%) (CI 95%)	Included studies number	Included patients number	Heterogeneity test, I‐squared (%) a	Heterogeneity test, p‐value a
Type A/B	All ages	7 (6–8)	207	194,931	97	<0.001
	<1 year	3 (4–18)	5	3291	85	<0.001
	<5 year	0.8 (0.1–5)	4	962	92	<0.001
	<18 year	2 (0.8–4)	24	15,229	56	0.05
	≥18 year	8 (6–10)	38	20,824	84	<0.001
	≥50 year	12 (6–22.5)	12	10,152	56	0.05
Type A (all subtypes)	All ages	6 (5–6.5)	133	98,545	94	<0.001
	<1 year	5 (0.7–25)	2	18	91	<0.001
	<5 year	1 (0.1–8)	3	775	89	<0.001
	<18 year	1 (0.1–8)	3	775	87	<0.001
	≥18 year	10 (8–13.5)	21	5735	92	<0.001
	≥50 year	16 (3–51)	6	7186	56	0.05
Type A (subtype H1N1)	All ages	5.5 (4–7)	84	88,603	97	<0.001
	In ICU cases	25 (15.5–37.6)	8	2838	91	<0.001
	<1 year	4.5 (0.3–45)	1	10	0	1
	<5 year	–	–	–	–	–
	<18 year	1.5 (0.6–40)	10	3945	94	<0.001
	≥18 year	5.5 (3–8)	9	1105	40	<0.01
	≥50 year	17.5 (12–25.5)	2	120	96	<0.001
Type A (subtype H3N2)	All ages	1.7 (0.2–15)	4	68,579	87	<0.001
	<1 year	5 (0.7–28)	2	17	8	0.1
	<5 year	–	–	–	–	–
	<18 year	1.5 (0.6–4)	10	3945	9	<0.001
	≥18 year	2.5 (4–14)	4	825	65	0.003
	≥50 year	–	–	–	0	0.4
Type A (subtype H5N1)	All ages	42 (29–56)	5	146	56	0.05
	<1 year	–	–	–	–	–
	<5 year	–	–	–	–	–
	<18 year	77 (48–92)	1	13	87	<0.001
	≥18 year	40 (28–51)	1	67	87	<0.001
	≥50 year	–	–	–	–	–
	All ages	30 (25.6–35)	11	1018	52	0.02
Type A (subtype H7N9)	All ages	2 (1–5)	4	291	0	0.5
Type A (non‐H1N1)	All ages	3 (2–4)	13	2812	87	<0.001
Type B	<1 year	–	–	–	–	–
	<5 year	–	–	–	–	–
	<18 year	2.5 (0.7–7.6)	3	1550	53	0.1
	≥18 year	–	–	–	–	–
	≥50 year	2.5 (0.7–7.6)	3	1550	89	<0.001

Abbreviation: ICU, intensive care unit.

^a Greater than 50% is considered high heterogeneity, less than 50% is considered low heterogeneity. A low p‐value (<0.05) is consistent with high heterogeneity.